Abstract
SOFL is a formal language and method for system specification and design. As a language it is an integration of Petri nets, data flow diagrams, and VDM-SL. As a method it is a combination of a structured method and object-oriented method. We introduce a graphical user interface (GUI) for supporting the construction of SOFL specifications, and a tool for testing SOFL specifications. With those tools it would be easy to construct a SOFL specification that consists of condition data flow diagrams, modules, and classes and to ensure its consistency and validity.